This is a very good and delicious soup that can help you get rid of leftovers. But can also be made with fresh ingredients. Whichever way you choose to make it is a very appetizing soup when properly made and is very helpful when one is not hungry but has to eat. The eggs and characteristic seasonings exist in all kinds of Hot and Sour Soups. As to the other things you can ad lib; they can be fish, shrimps, meat, bean curd, etc. Even the water itself can be replaced by chicken soup, chicken broth, meat soup, made from boiling meat bones, adding chicken bouillon etc.